Altitude ARM switch
Altitude ARM annunciator
Selected altitude display
Altitude select knob
Figure 3-13. Altitude Select Controller
b. Controls and Functions.
(5) Altitude arm annunciator.
(1) Altitude ARM switch. Pressing the ARM
annunciator will display when altitude ARM has been
(altitude arm) switch arms the altitude select controller.
ARM annunciation will display in the display window.
3-24. NAV 1 Receiver (KNS 81).
The ALT ARM annunciator, located in the flight director
mode annunciator panel on the pilot's instrument panel
a. Descriptions. The KNS 81 is a self-contained
navigation system consisting of a 200-channel
VOR/LOC receiver, a 40-channel glideslope receiver,
Within approximately 1000 feet of the preselected
and a digital RNAV computer with preselection storage
altitude, ALERT will be displayed in the display window
and will remain displayed until reaching approximately
The receiver interfaces with the pilot's TACAN/DME,
300 feet of the selected altitude.
displaying bearing information on the HSI and RMI. It
(2) Selected altitude display.
receives and interprets VHF omnidirectional radio range
(VOR) and localizer (LOC) signals in the frequency
altitude selected with altitude select knob.
range of 108.00 to 117.95 MHz; glideslope signals in the
(3) Altitude select knob.
frequency range of 329.15 to 335.00 MHz: and marker
beacon signals to 75 MHz.
(a) Inner knob. Used to select 100 foot
increments of desired altitude
The system incorporates three TACAN modes
(TAC, TAC RNV, TAC RNV APR), three VOR modes
(b) Outer knob. Used to select 1000
(VOR, VOR RNV, VOR RNV APR). and an ILS mode.
foot increments of desired altitude.
System flexibility is maintained with CHK and RAD
buttons. The CHK button, when pressed, permits a
(4) Altitude alert annunciator. Will display
momentary display of the TAC/VOR radial and
when the aircraft is within approximately 1000 feet, and
DME distance information in the display window.
will extinguish when reaching/deviating approximately
300 feet of the selected display.
Change 5 3-21